Synonyms:
* Happy: Joyful, cheerful, delighted, glad, elated
* Sad: Depressed, unhappy, sorrowful, mournful, gloomy
* Big: Large, huge, enormous, gigantic, massive
* Small: Tiny, little, miniature, petite, diminutive
* Hot: Warm, boiling, scorching, fiery, sweltering
* Cold: Chilly, freezing, frosty, icy, frigid
* Strong: Powerful, mighty, robust, sturdy, tough
* Weak: Feeble, frail, delicate, fragile, flimsy
* Good: Excellent, wonderful, superb, brilliant, fantastic
* Bad: Terrible, awful, dreadful, horrible, atrocious
Antonyms:
* Happy: Sad, unhappy, miserable, dejected, sorrowful
* Big: Small, tiny, little, miniature, diminutive
* Hot: Cold, chilly, freezing, frosty, icy
* Strong: Weak, feeble, frail, delicate, fragile
* Good: Bad, terrible, awful, dreadful, horrible
* Light: Dark, dim, shadowy, obscure, opaque
* Up: Down, below, beneath, under, underneath
* Fast: Slow, sluggish, leisurely, deliberate, tardy
* Open: Closed, shut, sealed, locked, restricted
* Clean: Dirty, filthy, soiled, stained, messy
Note: The specific synonyms and antonyms can vary depending on the context and the specific nuance of the word.